This invention relates to rehydration of activated green ceramic. More particularly, it relates to the rehydration of green ceramics which have been molded into shaped structures, such as by extrusion, into thin-wall shapes.
In the preparation of activated ceramics for catalyst supports or the like, it is customary to first activate, or dehydrate, the ceramic and then to rehydrate the ceramic prior to subsequent reactivation and firing. The initially activated ceramic may, at times, prior to rehydration be formed into a slip or doughy-like substance by the addition of small amounts of water, and optionally plasticizers thereto, followed by molding or extrusion of the green ceramic into a particular shape. When such a shape comprises a thin-walled object it has been found to be difficult to control the rehydration of the green ceramic without incurring cracking or the like which is believed to be due to a premature drying out of the wall.
It is therefore an object of this invention to provide a system for the rehydration of molded green ceramics to inhibit or prevent the previous deleterious effects as discussed above. It is a particular object of the invention to provide a system for rehydration of green ceramic which has been extruded into a thin-wall green ceramic structure.